1. Field of the Invention
The present invention relates to a cleaning apparatus for removing dirt attached to a member included in image forming apparatuses such as copiers, facsimiles and printers, and more particularly to the cleaning apparatus including an electrically conductive brush attached to a brush roller for removing residual toner particles.
2. Discussion of the Background
In known image forming apparatuses such as copiers, printers and facsimiles, for example, a toner image is carried in the form of a sheet on a recording media, having been formed by an image forming mechanism such as electro-photography, for example. The toner image which is carried on the recording medium is formed on an image bearing body, such as photoreceptor, for example, before being transferred to the recording medium.
In an image forming apparatus, for example, an electrophotographic image forming apparatus, the peripheral surface of a cylindrical electrophotographic photoreceptor, i.e., photoconductive drum as an image bearing member, is uniformly charged, and an electrostatic latent image is formed on the uniformly charged peripheral surface in accordance with image formation data. This electrostatic latent image is visualized with the use of developer, that is, a toner image is formed. Then, the toner image is transferred from the photoreceptor onto a piece of transfer medium, i.e., recording medium, and is fixed to the transfer medium, to obtain a copy or a print.
Up to now, a cleaning apparatus has been utilized in an image forming process of a toner image in order to clean the peripheral surface of the image bearing body, a charging roller and a transfer belt which form a toner image onto a recording medium. The cleaning apparatus removes residual toner particles attached to the cleaning target and dirt such as paper dust.
In unexamined Japanese Laid-Open Patent Application Publications No. 6-095570 and 7-140763, a cleaning apparatus is known to include a brush roller which is placed in contact with the peripheral surface of the target for cleaning. In the cleaning apparatus of this kind, the brush roller is rotated by a driving apparatus. Difference between the linear velocity of a brush brought into contact with the peripheral surface of a cleaning object and the linear velocity of the cleaning target causes residual foreign substance to be swept away, cleaning the peripheral surface of photoreceptor.
In unexamined Japanese Laid-Open Patent Application Publication No. 2002-221883, a brush with a bristle of approximately 2 mm or less in length is proposed. However, the foreign substance is cleaned not by a difference of linear velocity between a brush roller and the cleaning target but by using elastic deformation to hold one edge of the bristle in contact with the peripheral surface of a cleaning target.
However, when foreign substances such as toner and paper dust, for example, are strongly adhered to the cleaning target, the foreign substances are not removed by the above-described removing mechanisms. If the foreign substances continue to accumulate, a blurred line may be printed during operation of the image forming apparatus.